HAVE you experienced buying an aquarium fish in a plastic bag only to find it dead within 48 hours or less? Chances are the plastic used to transport the fish is highly toxic. Based on a study conducted by marine scientist Heather Hamlin from the University of Maine in the United States, some plastic bags leach nonylphenol (NP) in concentrations that are highly toxic to fish. In a report by Phys.org, they indicated that some of the plastic bags tested by Hamlin and colleagues had FDA food-grade rating and are being used for human food and cleaning agents like detergents.

FISH IN TROUBLED WATER. A NEW STUDY BY A MARINE EXPERT SUGGESTS THAT CERTAIN CLEAR PLASTIC BAGS MAY BE DEADLY TO FISH AS THEY LEACH HIGH AMOUNT OF TOXIC MATERIALS.

These plastic bags' level of toxicity to fish is enough to damage the DNA and alter the fertility in fish as NP binds to estrogen receptors. In a video, Hamlin explained that they investigated two kinds of plastic bags that are labeled identically as FDA food-grade polyethylene. One proved to be highly toxic to fish and leached high amount of NP that killed 60 percent of the fish in the study after a 48-hour exposure. The other FDA food-grade bag tested had high survival rate of 89 percent and fish that were kept in glass bowls soon after purchase survived the full 48 hours. “We wanted to understand if NP can leach and become toxic to fish. We found that these bags are used beyond the ornamental fish trade but also for food packaging such as bread bags or other food packaging material so the problem with these toxic plastic bags extends to humans as well,” Hamlin said. She urges the public to look for alternative to plastic bags in transporting ornamental fish from the store to aquariums. A glass container, she said, should contain the fish temporarily instead of plastic bags.

In the Philippines, it is very common for petshops to sell ornamental fish and place them inside plastic bags with just enough water and oxygen. Statistically, however, expert aquarists and animal experts say the mortality rate of wild-caught marine fish is so high that 98 of every 100 die within a year.